Ratchet wrench with safety collar



Oct. 19, 1954 M. GRIAK ETAL 2,691,910

RATCHET WRENCH wrm SAFETY COLLAR Filed March 2, 1953 FIELl- Patented Oct. 19, 1954 UNITED STATS PATENT OFFICE Mike Griak and Arthur 0. Hammer, Duluth, Minn.

Application March 2, 1953, Serial No. 339,506

Claims.

This invention relates to improvements in ratchet-type wrenches.

A ratchet-type wrench commonly includes a double pawl which can be set selectively in either of two operating positions to enable the wrench to turn another member either clockwise or counterclockwise. In some circumstances after a wrench is used to turn a member part way, a positive torque is set up in the member. This torque can throw the pawl to its opposite position, whereby the wrench handle turns with the member in the same way as a rigid-type wrench, and can be extremely hazardous to the operator. One example where such a torque occurs is in opening a hopper bottom railroad car. The wrench is used to turn a shaft on which the hopper doors are mounted until the doors release themselves. Thereupon the load behind the doors often forces them open very rapidly and spins the shaft. A rigid-type wrench cannot safely be used for opening such doors because of this spinning action, and often the usual ratchettype wrench acts the sarne way and consequently also is unsafe.

An object of the present invention is to provide an improved ratchet-type wrench which embodies a safety device for preventing its pawl from being thrown to its opposite position on a sudden application of torque.

A further object is to provide an improved ratchet-type wrench which includes a shiftable safety collar that positively prevents the pawl from engaging the ratchet in other than the position where set.

l'n accomplishing these and other objects of the invention, we have provided improved details of structure, a preferred form of which is shown in the accompanying drawing, in which:

Figure 1 is a top plan view of a ratchet-type wrench which is equipped with an improved safety device constructed in accordance with the present invention;

Figure 2 is a fragmentary top plan view on a larger scale showing the safety device and its re lation to the operating parts of the wrench, the parts being set for clockwise turning;

Figure 3 is a view taken on line III-III of Figure 2; and

Figure 4 is a top plan View of the wrench with the parts set for counterclockwise turning.

The wrench to which our invention is applied includes a handle and a pawl and ratchet mechanism which can be of any standard suitable construction. The wrench illustrated includes a handle which is formed of an operating lever I0 and spaced apart side plates I2 and I3 fastened to the opposite faces of said lever. A ratchet nut I4 is rotatably mounted in circular openings in said side plates, and a pawl l5 is pivotally mounted in the space between said side plates on a pivot pin I6. The ratchet nut has an openu ing Ma adapted to fit over a member to be rotated and the outer circumference of this nut has ratchet teeth I'I, which are situated between the two side plates. The pawl is double and has a finger Ia which engages the ratchet teeth for clockwise turning and a second finger IED which engages these teeth for counterclockwise turn-- 111g.

A pawl keeper I8 is slidably mounted in a longitudinal socket in the end of the handle IG. A compression spring i9 is mounted in this socket behind the pawl keeper and tends to urge the latter outwardly. The mid-portion of the pawl is contoured to engage the keeper. When the pawl is set for clockwise turning, as shown in Figures 1 and 2, the keeper and spring are yieldable to allow the pawl to ride over the ratchet teeth during counterclockwise return movement of the handle. Similarly when the pawl is eet for counterclockwise turning as shown in Figure 4, the keeper and 'spring allow the handle to turn clockwise in its return movement. Normally the keeper exerts sucient force to prevent the pawl from turning all the way to its opposite setting, although it can be manually thus turned when desired. However, in the absence of our safety device described hereinafter, a sudden torque can throw the pawl to its opposite setting where it in effect locks the handle l to the ratchet nut I4 and creates a serious safety hazard.

In accordance with the present invention, a safety collar 20 is mounted on the upper face of the ratchet nut lll, being retained by a plate 2l and screws 22 fixed to the top of said nut. The collar 20 and nut I4 are capable of relative rotation. The circumferential edge of the collar has two spaced apart notches 23 and 23a. The upper face of the side plate I2 carries a detent housing 24, preferably welded thereto. A detent or latch 25 is slidably mounted in said housing, and a compression spring 26 is mounted in the housing behind the detent and urges the latter outwardly. The collar 20 can be turned so that either of its notches 23 or 23a selectively registers with the detent 25 and thus latches the collar to the handle so that in the usual operation of the wrench the collar moves with the handle.

The circumferential edge of the collar 20 carries a pair of spaced apart downturned lugs 2'! and 21a which extend over the space between the two side plates I2 and I3 as shown in Figure 3. When the collar is turned to the position where its notch 23 registers with the latch means 25, as shown in Figures 1 and 2, lug 21 blocks the pawl finger 15b from engaging the ratchet teeth IT. Similarly, when the collar is turned to its other position where notch 23a registers with the latch means as 'shown in Figure 4, lug 21a blocks the pawl nger Ia from engaging these ratchet teeth. The collar is turned to the first of these positions when the pawl l5 is Set for turning a member clockwise and to the second position when the pawl is set for turning a member counterclockwise. Thus the safety collar positively prevents either iinger other than that 4desired from engaging the ratchet teeth.

From the foregoing description, it is seen that our invention affords a simple safety device for preventing a ratchet wrench from reversing and thus preventing its handle from spinning with a member with which the wrench is engaged. The device can be applied to existing wrenches without otherwise altering their structure.

While we have shown and described ,only a single embodiment of the invention, it is apparent that modifications may arise. Therefore we do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

We claim:

1. In a ratchet-type wrench which includes a handle, a ratchet nut supported on said handle for rotation relative thereto and carrying ratchet teeth, and a double pawl pivoted to said handle and having two iingers selectively engageable with said teeth, said pawl having a setting in which one of its iingers engages said teeth for clockwise turning and a second setting in which its other linger engages said teeth for counterclockwise turning, the combination with said handle of a safety device comprising a collar, means mounting said collar for normally rotating with said handle relative to said nut, and means on said collar extending over some of said teeth, said collar having two operating positions in which said last named means selectively blocks one of said pawl fingers from engaging said teeth while permitting the other finger to engage the teeth.

2. In a ratchettype wrench which includes a handle, a ratchet nut supported on said handle for rotation relative thereto and carrying ratchet teeth, and a double pawl pivoted to said handle and having two fingers selectively engageable with said teeth, said pawl having a setting in which one of its ngers engages said teeth for clockwise turning and a second setting in which its other nger engages said teeth for counterclockwise turning, the combination with said handle of a safety device comprising a collar, means mounting said collar for normally rotating with said handle relative to said nut, means on said collar extending over some of said teeth, and latch means carried by said handle, said collar having spaced apart notches selectively registrable with said latch means to position said collar to block one of said pawl iingers from engaging said teeth While permitting the other iinger to engage the teeth.

3. In a ratchet-type Wrench which includes a handle, a ratchet nut supported on said handle for rotation relative thereto and carrying ratchet teeth, and a double pawl pivoted to said handle and having two fingers selectively engageable with said teeth, said pawl having a setting in which one of its iingers engages said teeth for clockwise turning and a second setting in which its other iinger engages said teeth for counterclockwise turning, the combination with said handle of a safety device comprising a collar positioned alongside one face of said nut, means on said nut mounting said collar for normally rotating with said handle relative to said nut, at least'one lugvon said collar extending over some of said teeth, and latch means carried by said handle, said collar having spaced apart notches selectively registrable with said latch means to position said collar where said lug blocks one of said pawl ngers from engaging said teeth while permitting the other linger to engage the teeth.

4. A combination as defi-ned in claim 3 wherein there are two spaced lapart lugs, each of which is adapted to block a diierent one of said pawl ingers from engaging said teeth in the difierent positions of said collar.

5. In a ratchet-type wrench which includes a handle formed of an operating lever and spaced apart side plates iixed to opposite faces of said lever, a ratchet nut supported by said side plates for rotation relative thereto and carrying ratchet teeth around its circumference between said side plates, a double pawl pivoted to said side plates therebetween and having two fingers selectively engageable with said teeth, and a pawl keeper between .said side plates normally retaining said pawl in the position to which it is set, said pawl having a setting in which one of its fingers engages said teeth for clockwise turning and a second setting in which its other .finger engages said .teeth for counterclockwise turning, the combination with one of said side plates of a safety den vice comprising a collar positioned alongside one face of said nut, means on said nut mounting said collar for normally rotating with said Yhandle relative to said nut, at least one lug on lsaid colla;` extending across the space between said side plates over some of said teeth, and latch means carried by one of said side plates, said collar having spaced apart notches selectively registrable with said latch means to position said collar where said lug blocks one of said pawl iingers from engaging said teeth while permitting the other finger to engage the teeth.

References cited in the sie of this patent UNITED STATES PATENTS Number yName Date 1,095,347 Nimsgern May 5, 1914 1,334,432 Bennett Mar. 23, 1920 1,436,610 Stantorf Nov. 21, 1922 2,233,091 Becker Feb. 25, 1941 2,544,795 Knudsen Mar. 13, 1951 FOREIGN PATENTS Number Country Date '7,164 Great Britain of 1900 

